Used as an intermediate in the synthesis of pharmaceuticals, particularly in the development of sulfonamide-based drugs. It plays a key role in introducing sulfonate or sulfonamide functional groups into organic molecules, which are common in bioactive compounds. Commonly employed in research settings for modifying peptide structures or creating enzyme inhibitors. Its reactivity makes it valuable in forming carbon-nitrogen and sulfur-nitrogen bonds during drug discovery processes. Handle with care due to its moisture sensitivity and potential to release hydrochloric acid upon decomposition.